• BMB Reports
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• v.43 no.5
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• pp.362-368
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• 2010

Dermcidin is a human antibiotic peptide that is secreted by the sweat glands and has no homology to other known antimicrobial peptides. As an initial step toward understanding dermcidin's mode of action at bacterial membranes, we used homonuclear and heteronuclear NMR to determine the conformation of the peptide in 50% trifluoroethanol solution. We found that dermcidin adopts a flexible amphipathic $\alpha$-helical structure with a helix-hinge-helix motif, which is a common molecular fold among antimicrobial peptides. Spin-down assays of dermcidin and several related peptides revealed that the affinity with which dermcidin binds to bacterial-mimetic membranes is primarily dependent on its amphipathic $\alpha$-helical structure and its length (>30 residues); its negative net charge and acidic pI have little effect on binding. These findings suggest that the mode of action of dermcidin is similar to that of other membrane-targeting antimicrobial peptides, though the details of its antimicrobial action remain to be determined.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.49.3-50
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• 2016

Deep Ecliptic Patrol of the Southern Sky (DEEP-South) observations have been conducted officially during the off-season for exoplanet search since October 2015. Most of the allocated time for DEEP-South is devoted to targeted photometry, Opposition Census (OC), of Near Earth Asteroids (NEAs) to increase the number of such objects with known physical properties. It is efficiently achieved by multiband, time series photometry. This Opposition Census (OC) mode target objects near their opposition, with km-sized PHAs in the early stage and goes down to sub-km objects. Continuous monitoring of the sky with KMTNet is optimized for spin characterization of various kinds of asteroids, including binaries, satellites, slow/fast- and non-principal axis-rotators, and hence is expected to facilitate the debiasing of previously reported lightcurve observations. We present the preliminary lightcurves of NEAs from year one of the DEEP-South with our long term plan.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.511-514
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• 2010

Perfluorinated polymer($Cytop^{TM}$) was deposited on selective area of AlGaN/GaN HEMT structure using low cost and simple spin-coating method, and the electrical characteristics of the device was analyzed for application of passivation layer on semiconductors. Gate lag measurement results of $Cytop^{TM}$ passivated and unpassivated HEMT were compared. Passivated device shows improved 65 % pulsed drain current of dc mode value. Rf measurements were also performed. $Cytop^{TM}$ passivated HEMT have similar rf performance to PECVD grown $Si_3N_4$ passivated device. $Cytop^{TM}$ passivation layer may play an important role in mitigating surface state trapping in the region between gate and drain.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.25-33
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• 2004

In this paper, we briefly introduce the micro-vibration test bench of KARI and the test and analysis method of RWA(Reaction Wheel Assembly) micro-vibration. The micro-vibration of RWA is measured on a KISTLER dynamic plate which can measure the time signal of 6 DOF simultaneously up to 400Hz. Measured data are extensively evaluated with respect to the wheel spin rate to identify the complicate wheel dynamic characteristics, and the static/dynamic unbalances are estimated from the extracted first harmonic component as a part of evaluation process. The estimated static and dynamic unbalances. 0.79gcm and 17.4gcm² respectively. The structural resonance mode and two rocking modes observed as a results of its frequency analysis. Several higher order harmonic components observed, which come from its rotor shape as well as the wheel bearing characteristics.

• STI Policy Review
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• v.4 no.2
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• pp.55-73
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• 2013

Since the 1990s, the Japanese government has made considerable attempts at stimulating innovation with an aim to pull the country out of a possibly permanent economic decline. Several laws and policy initiatives were introduced to encourage better interaction between universities (and research institutions) and industry. The results of these efforts have been mixed. While the number of university-industry joint and commissioned research has increased, revenues from the licensing of university-owned patents have fluctuated year by year. Although the number of startups and spin-offs from universities rose, their long-term survival and contribution to the economy remain uncertain. The Japanese experience features both strengths and weaknesses. Strengths include the long-term commitment of policy makers, the ability to set specific targets, and the active engagement of several key economic ministries. Nevertheless, the effectiveness of these policy initiatives was hampered by limitations within the policies concerning the roles of universities and their mode of interaction with industry based on intellectual property rights, the inadequacy of demand-side innovation policies, the fragmentation of bureaucracy, and a lack of a credible evaluation system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.695-698
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• 2004

STSAT RWA (Reaction Wheel Assembly) micro-vibration is measured using KISTLER dynamic plate that can provide the time signals of three orthogonal forces and torques simultaneously up to 400Hz. In the post-processing, measured data are evaluated with respect to the wheel spin rate in both time and frequency domains, and the static/dynamic unbalances are evaluated from the extracted first harmonic component. Also the friction torque profile at each wheel speed is estimated from the measured data. Several higher order harmonic components are observed, that comes from its rotor shape as well as the wheel bearing characteristics. One of the most peculiar characteristics of this wheel is that the dynamic properties of two radial unbalance components are much different from each other as the RWA mounting configuration on a spacecraft is different from conventional RWA mounting configuration. Rocking mode is not appeared below 400Hz for all operating speed because the wheel size is very small. The post-processed results will be used for jitter analysis of STSAT due to RWA micro-vibration.

• Journal of the Korean Magnetics Society
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• v.7 no.3
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• pp.129-133
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• 1997

To investigate the influence of the Hf concentration and the annealing effect in $Co_{1-x}Hf_x$(X=0.16, 0.24 at.%) systems, ferromagnetic resonance experiments have been carried out. Spin wave resonance spectra for all samples consist of several volume modes and one (or two) surface mode. It is suggested that both surfaces of the film have a perpendicular hard axis to the film plane (negative surface anisotropy). The surface anisotropy $K_{s2}$ at substrate-film interface is varied slowly from -0.07 to -0.32 erg/$\textrm{cm}^2$ and the surface anisotropy $K_{s1}$ at film-air interface is varied from 0.18 to -0.47 erg/ $\textrm{cm}^2$ with increasing annealing temperature in the amorphous $Co_{84}Hf_{16}$ thin films. Also, the surface anisotropy $K_{s2}$ is varied slowly from -0.31 to -0.41 erg/$\textrm{cm}^2$ and the surface anisotropy $K_{s1}$is varied from -0.19 to -0.60 erg/$\textrm{cm}^2$ with increasing annealing temperature in the amporphous $Co_{84}Hf_{16}$ thin films. We conjecture that the variation of surface anisotropy $K_{s1}$ is due to the increase of Co concentration resulted from Hf oxidation for low temperature annealing(150~175 $^{\circ}C$) and the diffusion of Co atoms near the film surfaces for high temperature annealing (200~225 $^{\circ}C$).

• Journal of the Korean Magnetics Society
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• v.7 no.1
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• pp.38-43
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• 1997

For amorphous $Co_{1-x}Ti_x$(X=0.13, 0.16, 0.21 at.%) thin films deposited by DC magnetron sputtering method ferromagnetic resonance experiments have been used to investigate the dependence of surface magnetic properties according to annealing temperature (150~225 $^{\circ}C$). Spin wave resonance spectra for all annealing temperatures consist of several volume modes and one(or two) surface mode. It is suggested that both surfaces of the film have a perpendicular hard axis to the film plane(negative surface anisotropy). Also, the surface anisotropy $K_{s2}$ at substrate film interface is varied slowly from -0.11 to -0.25 erg/ $\textrm{cm}^2$ and the surface anisotropy $K_{s1}$ at film-air interface is varied from 0.16 to -0.53 erg/ $\textrm{cm}^2$ with increasing annealing temperature. We conjecture that the variation of surface anisotropy $K_{s1}$ is due to the increase of Co concentration resulted from Ti oxidation for low temperature annealing(150~200 $^{\circ}C$) and the diffusion of Co atoms near the film surfaces for high temperature annealing(225~250 $^{\circ}C$).

• Korean Journal of Crystallography
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• v.12 no.4
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• pp.197-206
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• 2001

A stoichiometric mixture of evaporating materials for AgInS₂ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films. AgInS₂ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy(HWE)system. The source and substrate temperatures were 680℃ and 410℃, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of AgInS₂ single crystal thin film mea-sured from Hall effect by van der Pauw method are 9.35×10/sup 16/㎤ and 294㎠/V·s at 293K respectively. The temperature dependence of the energy band gap of the AgInS₂ obtained from the absorption spectra was well described by the Varshni's relation , E/sub g/(T)=2.1365eV-(9.89×10/sup-3/eV/K/)T²(T+2930K). The crystal field and the spin-orbit splitting energies for the valence band of the AgInS₂ have been estimated to be 0.1541eV and 0.0129 eV, respectively, by means of the photocur-rent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the Δso definitely exists in the Γ/sub 5/ states of the valence band of the AgInS₂ /GaAs epilayer. The three photo-current peaks ovserved at 10K are ascribed to the A₁-, B-₁and C₁-exction peaks for n=1.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.5
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• pp.179-186
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• 2007

Single crystal $CdGa_2Se_4$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with the hot wall epitaxy(HWE) system by evaporating the polycrystal source of $CdGa_2Se_4$ at $630^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of single crystal $CdGa_2Se_4$ thin films measured with Hall effect by van der Pauw method are $8.27{\times}10^{17}cm^{-3},\;345cm^2/V{\cdot}s$ at 293 K, respectively. The photocurrent and the absorption spectra of $CdGa_2Se_4/SI$(Semi-Insulated) GaAs(100) are measured ranging from 293 K to 10 K. The temperature dependence of the energy band gap of the $CdGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation $E_g(T)=2.6400eV-(7.721{\times}10^{-4}eV/K)T^2/(T+399K)$. Using the photocurrent spectra and the Hopfield quasicubic model, the crystal field energy(${\Delta}cr$) and the spin-orbit splitting energy(${\Delta}so$) far the valence band of the $CdGa_2Se_4$ have been estimated to be 106.5 meV and 418.9 meV at 10 K, respectively. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1^-},\;B_{1^-},\;and\;C_{11}-exciton$ peaks.